1 PREP书上的

What’s the value of 3x²+6x-4 ?

(1)    x(x+2)=0

(2)    -1<x<4

我认为是A，但是给出的解释和答案是C

2 GWD上的

If n is an integer and 100 < n <200, what is the value of n?

(1) n/36 is an odd integer.

(2) n/45 is an even integer.

我认为是B，但是答案是C

3 GWD上的

At a certain company, each employee has a salary grade s that is at least 1 and at most 5. Each employee receives an hourly wage p, in dollars, determined by the formula p = 9.50 + 0.25(s – 1). An employee with a salary grade of 5 receives how many more dollars per hour than an employee with a salary grade of 1?

A.      $0.50

B.     $1.00

C.     $1.25

D.     $1.50

E.     $1.75

我认为是B，答案是C

4 GWD上的

The ratio of the number of red cars in a certain parking lot to the number of black cars is 3 to 8. If there are 72 black cars in the lot, how many red cars are there in the lot?

A.     11

B.     15

C.    24

D.    27

E.     32

我选了D，答案是C，怎么算也算不到